This invention relates generally to air conditioning systems and more particularly concerns systems for transfer of refrigerant from a source to a receiving unit.
In our U.S. Pat. No. 5,230,224, maximizing recovery of refrigerant from a disabled refrigeration unit was accomplished by the series connection of a vacuum pump and a compressor. The present invention is directed to maximizing the percentage of new or recovered refrigerant drawn from a source container to charge or recharge a refrigeration unit.
In the standard method presently used by most air conditioning technicians to charge or recharge an air conditioning unit refrigerant flows under pressure differential from a source container into the suction side of the compressor on the air conditioning unit for a short period of time. The air conditioner is then turned on and permitted to run until the pressure is equalized between the source container and the air conditioning unit. Using this method, after charging or recharging the air conditioning unit, as much as fifteen per cent or more of the refrigerant remains in the source container. Several million pounds of refrigerant are manufactured each year in the United States and up to fifteen per cent of it will be released to the atmosphere using the standard charging method above described. At approximately $2.41 to $9.01 per pound of refrigerant, the direct economic loss is staggering, to say nothing of the unknown problems resulting to the ozone and our atmosphere.
Efficiency in capturing new refrigerants from the container is also poor. Empty cans selected at random from those discarded by contractors after charging air conditioning units with new refrigerant are typically found to still contain an average of in excess of 11/2 pounds of refrigerant, or at least five percent of the total contents of a standard can. At least five per cent and perhaps as much as fifteen per cent of all new refrigerants sold in the United States in 1993 will be wasted.
It is, therefore, the primary object of this invention to provide an automatic charge and recharge refrigerant transfer system which transfers or recovers greater quantities of refrigerant from a container than is recovered using presently known charging and recharging methods.